Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie
Hi there,
There is an issue with role permissions that is being worked on at the moment.
If you are having trouble with access or permissions on regional forums please post here to get access: https://www.boards.ie/discussion/2058365403/you-do-not-have-permission-for-that#latest

Help please!!

  • 05-10-2008 2:16pm
    #1
    sleepypinkmoose
    Registered Users, Registered Users 2 Posts: 28 ✭


    I have been doing questions for ages and getting them wrong.. please help?:confused::confused::confused::confused::confused::confused::confused::confused::confused::confused::confused:
    OK so I know (x+y)2 = x2+ 2xy + y2

    and (x-y)    2= x2 - 2xy + y2

    but WHAT IN THE WORLD is (-x-y)    2

    (the small 2's are meant to mean "squared")

    THANKS :D


Comments

  • #2
    sleepypinkmoose
    Registered Users, Registered Users 2 Posts: 28 ✭sleepypinkmoose


    finally realised it is the same as (x+y)2

    thank god!

    back to study......:cool:


  • #3
    Pherekydes
    Registered Users, Registered Users 2 Posts: 16,226 ✭✭✭✭Pherekydes


    sleepypinkmoose wrote: »
    finally realised it is the same as (x+y)2

    thank god!

    back to study......:cool:

    To denote x squared write X^2. That's the usual convention online.

    (-x-y)^2 = (x+y)^2 because

    (-x-y)^2 = {(-1)(x+y)}^2 = (-1^2)(x+y)^2 = (1)(x+y)^2

    Thanks.


  • #4
    LeixlipRed
    Closed Accounts Posts: 6,081 ✭✭✭LeixlipRed


    Your brackets are wrong there in the last line. Should be {(-1)(x+y)}^2


Advertisement